In wire harnesses that are installed in automobiles and the like, often, a coating of an insulation-coated wire is partially stripped to expose a conductor composed of a group of elemental wires, and another wire is connected to the exposed portion of the conductor by welding or by using a crimp terminal, or a connection terminal is crimped onto the exposed portion of the conductor. In cases where such an exposed portion of a conductor or an electrical connection portion is disposed in an area that may be exposed to water, reliable waterproofing is required.
Therefore, conventionally, a branch connection structure has been proposed in which a terminal splice portion for branching a branch line from a trunk line of a wire harness serving as a communication line for an on-board network is housed in a protective cap made of resin, and this protective cap is fixed to a portion near end portions of respective coatings of the trunk line and the branch line by winding tape therearound or by using a heat-shrinkable tube or a water blocking agent (see JP 2008-131327A, for example).
Also, a waterproofing device has been proposed in which a core wire (conductor) exposed portion that is uncoated is formed at an intermediate portion of a plurality of coated lead wires that are bent upward in an inverted U shape, and a waterproof and heat-resistant insulating tube that is bent in an inverted U shape is provided, the insulating tube covering the core wire exposed portion of the plurality of coated lead wires (see JP 2000-113917A, for example).
JP 2008-131327A and JP 2000-113917A are examples of related art.
However, the former conventional water blocking structure for an insulation-coated wire, in which the terminal splice portion is contained in the protective cap, cannot be used for waterproofing of an intermediate splice portion.
On the other hand, even though the latter conventional water blocking structure for an insulation-coated wire, in which a plurality of coated lead wires having the core wire exposed portion are bent in an inverted U shape, can be used for blocking water at the conductor exposed portion in the intermediate portion or waterproofing of the intermediate splice portion, there are unsolved problems as described below.
That is to say, in the latter conventional water blocking structure for an insulation-coated wire, the insulation-coated wire with the conductor exposed portion formed at an intermediated portion thereof is inserted into the insulating protective tube, and that insulation-coated wire is folded in an inverted U shape together with the insulating protective tube at a position different from the conductor exposed portion that is easy to bend. Therefore, the operation of bending that insulation-coated wire and the insulating protective tube is not easy and thus increases the manufacturing cost. In addition, the insulating protective tube after bending tends to be corrugated or bent in the vicinity of the conductor exposed portion, and an end portion of the coating of the insulation-coated wire that is adjacent to the conductor exposed portion tends to be opened. Therefore, the water blocking ability may be easily deteriorated.
Furthermore, for both the conventional water blocking structures for an insulation-coated wire, a coating stripping operation of stripping off the coating at a predetermined position and in a section of a predetermined length in advance is indispensable. Therefore, in a case where, for example, a high level of water blocking performance is desired by preventing especially the intermediate portion of the insulation-coated wire from suffering secondary exposure to water from the terminal portion, the problems such as deterioration in workability and an increase in manufacturing cost cannot be avoided.